Receiver for wireless telegraphy.



No. 896,1`3. PATBNTED AUG. 1a, 190s.

f -G. MARCONI.

RECEIVER PGE WIRELESS TELEGRAPHY, I

v APPLICATION FILED MAR. 13, 1907.

Urs I srarss Asier cerros.

GUGLIELMO MARCONI, OF LONDON, ENGLAND, ASSIGNOR TO MARCONI WIRELESS TELE- GRAPH COMPANY OF AMERICA, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.`

i RECEIVER FOR WIRELESS TELEGRAPHY.

Specification of Letters Patent.

Patented Aug. 18, 1908.

Application led March 13, 1907. Serial No. 362,121.

To all whom'it Imay concern:

Be it known that I, GUGLiELMo MARCONI, LL. D., D. Sc., a sub'ect of thc` King of ltaly, residing at 1S Fincli Lane, in the city of London, England, have invented new and useful lmprovimicnts in Receivers. for Wireless Telcgraphy, of which thcfollowing is a specification.

This invcntion relates to a method of emio ploying the well known Flomings oscillation valve (described in thel U. S. A. spcciiication No. $03684) in wireless telegra. ihy. This valve consists ol' a vacuous vessel having in it two conductors adjacent to but not touching each other one conductm being heated in any convenient manner while the other is connected to an external circuit.

'lhe oscillation valve is preferably placed inshunt with the secondary ol the step-up o transformer or fr, which is, as usual, connected with theI aerial. rl`hc. circuit including thi-.secondary coil of the jiggcr and the oscillation valve., also includes the primary or iinc wire winding of the induction coil or step-down transformer, the secoiidar f winding of which is connected with a telephone receiver, relay, or other suitable wave responsive device. for detecting the received signals.

A condcnsn' may be placed in series be.- twecii the Yalve and the induction coil and a second condenser in a shunt across the. ends of the secondary of the jiggcr.

ylhc condenser 'last mentioned., together with the secondary vwinding of the jigger, forms a closed oscillatory circuit when the capacity of this condenser is properly adjustcdlor syntonism.

The values of the' inductance and capacity 4o of the transformer or jigger and the value of the capacities of the condensers associated to it should 'ne such as to bring the receiving circuit, including said jiggcr into resonance with the period of the transmitted oscillations. The drawing is a diagram of the arrangement it is preferred to adopt.

a is a. glass bulb, and b is a carbon iilamcnt like the carbon lilament ol' an incandescent lam ,suitable say forv taking a current of (i to S vo ts and to 4 uinpercs. c isa cylinder of aluminium onen at the top and bottoni which surrounds but docs not touch the iilamcnt. The. cylinder c is sus cndcd and stcadicd by 5a platinum wires d, and the ends of thc iilanient b are connected to platinum wires connected to-the. leads e and f. The platinum wires are scaled throuefh the glass in the ordinary manner. 7i is a battery' by which the. filament b is heated. rlhis arrangement is one form 0f the oscillation valve described in the said yformer s ecification.

Oneo the wires d is connected to the secondary y' of the jigger the primary l of which is connected to the ordinary aerial l and to earth. 'lhe other end of the. seconda-ry is connected by a wire m to one end of the iine wire winding of an induction coil n (which should bc such as usually manufactured to give say a. i0 inch spark) the other endof its iine wire winding being connected by a. wire o through a condenser p to the lead e. Then thcinduction coil is thus connected, the fine wirewinding, .usually operating as a secondary winding, becomes the primary coil, while the coarse wirel winding, usually operating as the primary winding, becomes the secondary coil. The ends of tlie secondary of the coil n. are connected to a circuit q containing a detector s of any ordinary type such as a telephone or a relay o erating a printing instrument. t `is a condenser 1n a shunt across the secondary y' of the `igger.`

By using a condenser, sucili as the condenser t, in the resonant circuit, the receiving circuit not only may be more easily brought into syntonism with the received oscillations, but such condenser permits the oscillations in the resonant circuit to accumulate to such an `extent that their electroniotive force is suilicient' to overcome the resistance of the space lbetween the iilainent b and the cylinder c in the oscillation valve, thereby increasing the strength of the. waves rectified by said valve. Inasinuch as the electroinotive force of the oscillations rectified by the' oscillation valve is high, while its current value isl small, the induction coil n transiorinsthe eurrentso that it acts upon the detecting device `las one of lower poten- 100 tial and hiwhercurr'nt value. These conditions are, there-ione, the reverse of those usually found in detectors for electromagnetic waves heretofore used.

inasmuch as the fine wire winding of the induction coil n introduces a large amount of inductancc into the receiving circuit,.tlie condenser y) is introduced to counteract the same.

The pulsating current produced in the Ferias of the receiving circuit, comprising the vilament l), the wire e, the wire o, the condenser .7), thcine wire winding of the induction. coil n, and the wire m, results in an alterneting current in the' wires q and thedetector ltelcgraphyrthe combination with im oscillatory circuit, et an oscillation valve, an lnduction coil, the oscillation valve and the primary winding of the induction coll being connected in series end operatively connected with scid oscillatory circuit, Aand a detecting device connected with the secondary winding 4of 'said induction coil.

21. In :a receiving apparatus for wireless Q Sceneo -telegrephy, the.,.combinetion with aroscill# tory circuit including e. condenser, of an oscillation valve, an'in'ductioncoil, the oscillation j x L valve nud the primary Winding of the induction coil bein ,connected in series witlrl erich other but 1n s ary win ing-of said induction'coil.4

3. In a receivingfapparetus. for `wirelesa telegrcphy, the combination with an oscilla-n i tory' circuit, if en oscillation valve, an induction coil. and a comlegnser,i said valve, condenser and the primary winding of the induction coil being'connected in series and operntivelyconnected with' said oscillator circuit, and a-detecting device connecteciY GUGL ELMO MARCONI. ,l -Witnessesz v ,l

ROBERT B. RANSFORD, ARTHUR CARPMAEL, Jun.

unt with said condenser, and ,a A detectin deviceconnected with the secondwith the secondary windin of seid induction coiL 

